Basically copy coupon, view price history or create e-mail price alert. Best price?
, 1.8GHz, ROM: 128GB, GPU: IMG GE8320 600MHz; Manhattan 3.0: 9fps, EMMC, up to 128GB, Card Extend: Supports TF Card, Octa Core, DDR4X, OS: Android 10.0, CPU: MT6762V/WD, RAM: 4GB
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in Hong Kong. Hmmm… There is no active coupon in Banggood at this moment.
Link: Banggood product page
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGBV5100, Email5
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Here is price history (for all/most countries) for Blackview BV5100 4/128GB.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).